1. Field of the Invention
The invention relates to a content filtering system and more particularly to a system and method for controlling user access to a computer network using a content filtering router that filters requests for content by routing them based on their final destination addresses.
2. Description of the Related Art
The Internet is a loose network of networked computers spread throughout the world. Many of these networked computers serve content, such as Web pages, that are publicly accessible. This content is typically located through Internet addresses, such as <http://www.company.com/info/>, which usually consist of the access protocol or scheme, such as HyperText Transport Protocol (http), the domain name (www.company.com), and optionally the path to a file or resource residing on that server (info). This Internet address is also known as a Uniform Resource Locator (URL). A Domain Name System (DNS) is then used to convert the domain name of a specific computer on the network into a corresponding unique Internet Protocol (IP) address, such as 204.171.64.2.
Typically, users access content in one of two ways. The user can enter a URL into a text or address box on a Graphical User Interface (GUI) of a file manager or an Internet browser, such as MICROSOFT'S INTERNET EXPLORER™, and click “Go” or press “Enter.” Alternatively, the user can click on a Hyperlink. The Hyperlink links a displayed object, such as text or an icon, to a file addressed by a URL.
As the Internet grows in size and sophistication, more and more content is becoming accessible to users. This content can be easily accessed by anyone who has a client computer and Internet access. However, some of this content may be unsuitable or inappropriate for all Internet users. For example, violent or adult content may be inappropriate for children. Therefore, in some situations it is desirable to limit and/or control user access to such content. For example, businesses may want to restrict their employees from viewing certain content on the Internet. Likewise, parents may wish to block their children's access to violent or adult content on the Internet.
This restriction and/or control of user access to content on the Internet is otherwise known as content filtering. content filtering allows a system administrator to block or limit content based on traffic type, file type, Web site, or the like. For example, Web access might be permitted, but file transfers may not.
There have been numerous attempts to provide content filtering using special browsers and filtering programs. These special browsers and filtering programs typically screen content by word content, site rating, or by URL. The software provider of the special browsers or filtering programs typically keep a master list of objectionable content that must be periodically updated in the special browser or filtering program on the user's client computer.
However, these existing content filtering systems have a number of drawbacks. First, they need to be installed and configured on each and every client computer where controlled access is desired. Such installation and configuration can be time-consuming, inconvenient, and require a basic understanding of computer hardware and software. Additionally, from time to time, the user may be required to install bug-fixes, patches, or updates to configure or maintain the filtering software. This is because additional content must be continually added to a list of restricted sites. Typically, this list must be periodically downloaded and installed by a user to his/her client computer. Moreover, the software and continually growing list of restricted sites may consume valuable client computer memory, which, in some cases, may limit or effect overall client computer performance. What is more, many children are typically more computer savvy than their parents and often find ways to circumvent the content filtering software without their parent's knowledge.
Another approach to content filtering has been to place filtering software on a proxy server, so that entire networks connected to the proxy server can be filtered. The proxy server typically contains a list of restricted content that is periodically updated. However, each client computer connected to the proxy server must typically also include software that includes the filtering requirements appropriate for that particular client computer. Again this requires software to be installed and configured for each client computer. This is not only time consuming and inconvenient, but may consume much of a system administrators time. If each client computer is not appropriately configured, users may be blocked from content that they should otherwise have access to. Conversely, children and other restricted users may be able to get access to inappropriate content using a particular client computer that has not been configured to restrict such content.
In addition, updating lists of objectionable content is itself a challenge, as it has been estimated that approximately two million Web pages are added to the Internet each day. What is more, Internet search engines tend to display search results with the most recent content listed first. As a result, inappropriate content may actually be listed first in a list of search results, thereby rendering filtering software that does not include this content on its restricted list, ineffectual. Conventional content filtering has several other limitations., such as content filtering is provided on a computer by computer basis.
Therefore, a need exists for a content filtering system that is easily provisioned for one or more client computers with little or no user intervention, such as installation and configuration of software, or updating a list of filtered content, onto the user's client computer. Moreover, a need exists for a filtering system that cannot easily be circumvented, bypassed, tampered with, or disabled at the client computer level.